Telephone circuit



Oct. 26, 1948. H. M. HUGE 2,452,239

' TELEPHONE CIRCUIT Filed April 15, 1946 1s 1 11- a 1 TLUTL-L 11 mm? mm: YOHER J m LINE is p 1 ,INE

FIQZ.

INVENTOR.

HENRY MAE77N HUGE BY I a Patented Oct. 26, 1948 UNITED STATES PATENT OF FICE.

TELEPHONE CIRCUIT Henry Martin-Huge, Lorain, Ohio, assignor, by

mesne assignments, to,.Lorain Products Corpora-tion, Lorain, Ohio, a corporation of Ohio Application April.15, 1946, Serial No. 662,138

10 Claims.

1. This invention deals with atelephone circuit of the local battery or magneto type and-in particular with an A. C. operated circuit which replaces both the magneto and. the batteries in a telephone of this'type Itis. an object of my invention to supply a telephone with both ringing current and talkingcur.- rent from a single A. C,.--op,era ted unit and to provide a switching arrangement for adapting the unit to the telephone circuit.

Another object ofmy; invention is to provide rent rectifier and with the ringing. current con trolled by a push-buttonandthe talking current controlled by the receiverhook switch; and

Figure 2 is the schematic diagram of .a somewhat different form of. self-starting subharmonic generator having windings supplying the talk.-

ing current rectifierand having both the ringing and talking current controlled by a single pushbutton.

The advantagesofztelephone circuits of the 10.- cal-battery type are well known, particularly their adaptability to extremely long or poorly. maintained lines where common-battery circuits. do not, provide either. reliable transmission or. reliable signaling.

Nevertheless there are several disadvantages.

connected with this type oftelephone system, one being the need for the use of-ahand-crankoperated magneto for signaling, and another being the gradual deterioration of the dry-cell batteries ateach stationandthe needior and expense of the periodic replacement ofthese batteries.

My invention eliminates both of these disad vantages. and in addition provides a compact,

economical unitwhich can be fittedin considerably less-space than the-equipment itreplaces. It

.members.

therefore makespossible a considerablereduction in the overallsize of the telephone set.

The features of my invention will become apparent from a somewhat detailed discussion'of the drawings.

In Figure l, the three-legged saturablemagnetic' core structureof coupling transformer F carriesinputwinding 22 onits central member and-outputwindings l8: and 20 on its two outer outputwinding l8; and Zflwhich are in series.

The output windings-aresubstantially equal and are polarized .to substantially cancel in the output circuit-the voltage ofjtheinput; frequency which 4 is inducedfrom winding 22. The input and'output circuits aretherefore coupled in conjugate relationship, by; saturabletransformer means ll.

Input winding 22 may be energized from the A. C. powerline through the rectifier switch-memberslZv and [3. When energized in this manner, the arrangement just described comprises a self-starting subharmonic generator as described in my U. S. patent application, Serial N umber- 662,137, filed concurrently herewith and entitled Frequency reducer.

The inputbranch of the circuit is energized with both direct and alternating current through the action of the half-wave rectifier H, which produces an asymmetrical current wave through the inputwwinding.

The output circuit through capacitor latesat one--halfvthe. frequency supplied by the A. C. powerline andthe desired output voltage is obtained from the taps l9 and 25 on the output windings l8 andiurespectively.

Whenpush-button 29 is-operated, thecontact arm [2. engages contact I3 closing the normally open contactsto energize-the inputwinding 22 from the A. 0. power line through the half-wave rectifier H. Contact arm Mengagescontact l6 and connects output tap i9, to oneside of the telephone line. while output tap 2i ispermanently connected to-theother side of the telephone line.

Thuswhen the. push-button 29 is operated, the

frequency changer supplies the subharmonic ringing frequency to the. telephone line. The subharmonic-oscillations start very rapidly and thepushbutton may be operated to code the ringing signal in any required manner. The users, own te1ephone-ringer- 3 i being acrossv the telephone, line;

Capacitor 28 connected across thellzand 28.0sci-1- 3 gives an audible indication of the code being transmitted.

Winding 23 on the central member of the core I! is inductively coupled to the input winding 22. The full-wave rectifier 25 is energized from winding 23 to provide a talking current supply. A center-tap rectification circuit is shown, although any one of the several known rectifier circuits might be used. Filter inductance 26 is connected to the center tap 24 of winding 23 to filter the direct current output of the rectifier 25. The filter capacitor 21 is connected across the direct current output to complete the filtering of the talking current supply.

The remainder of the telephone circuit is, for the most part, a typical circuit of the local-battery type. An added element is the contact arm 33 and contact 34 operated by the receiver hook which holds the receiver 32.

When the receiver 32 is lifted from its hook, contact arm 33 engages contact 34 connecting the input winding 22 directly to the A. C. power line, and thereby energizing the rectifier 25 to supply the talking current. normally saturated under this condition, because the biasing current from rectifier II which saturates the core for the generation of subharmonics is not supplied when the contacts 33 and 34 are closed.

The receiver-hook contact arm 35 engages contacts 36 and 31 when the receiver 32 is lifted from its hook, thereby connecting the receiver 32 across the telephone line through condenser 30, the secondary of induction coil 39 and contact 36. At the same time the direct current from rectifier 25 is fed through contacts 36 and 31, through the primary of the induction coil 39, to the transmitter 38 to complete the talkingcurrent circuit. The telephone is thus conditioned for normal reception and transmission.

It will be noted that under this condition the ringing current supply is not connected across the telephone line, being disconnected at the normally open contact [6. Furthermore, the output taps l9 and 2| are short-circuited through the normally closed contacts I 4 and I5. This arrangement assures that no undesired oscillations will be excited by capacitor 28 while push button 29 is not operated. When this feature is not required, the contact 15 may be omitted.

If the receiver 32 is lifted from its hook while the push button 29 is operated, rectifier H is shorted through contacts 12, I3, 33 and 34 so that no ringing power is generated and the receiver is not subjected to an abnormally high voltage.

In Figure 2 a modification of the subharmonic generator of Figure 1 is shown. The saturable core structure of the coupling transformer I! has input windings 40 and 41 on its two outer members, and output winding 42 on its central member. Capacitor 28 is connected across output winding 42 for the excitation of subharmonic oscillations therein.

When push-button 29 is operated, the normally closed contacts 12' and 46 are opened, inserting the half-wave rectifier H in series with the input windings 40 and 4| which are energized from the A. C. power line. The input windings 40 and 4| are connected in series and are polarized to produce opposing fluxes in the central core member, making the input and output circuits conjugate.

The self-excited subharmonic oscillations in the output circuit are generated in essentially the The core l! is not same manner as in the arrangement of Figure l. The required subharmonic ringing voltage is obtained from winding 42 by the provision of a tap 43.

With push-button 29 operated, the ringing voltage is fed to the telephone line through contacts l4 and I6.

When push-button 29 is in the non-operated position, the normally closed contacts 12 and 46 short the rectifier l 1, connecting the input windings 49 and 4| directly to the A. C. power line to energize the rectifier windings 44 and 45. The center tap full-wave rectifier 25 is energized from the windings and 45 in series, and the centertap connection for the positive direct current lead is obtained at the junction between the two windings 44 and 45.

The direct current supply is filtered by the inductance 26 and capacitor 2'! as in Figure 1, and the remainder of the telephone circuit is substantially as shown in Figure 1.

The normally open contacts 33 and 34 shown in Figure 1 are omitted in Figure 2, the direct current supply being controlled by the pushbutton 29. Thus, the rectifier 25 is continuously energized, even when the receiver 32 is hanging on its hook.

It will be apparent that the various modifications shown in Figures 1 and 2 are interchangeable between the two figures and that other modifications which will be apparent to those skilled in the art may be employed without departing from the scope of my invention.

Although I have described my invention with a certain degree of particularity, it is to be understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.

I claim as my invention:

1. In a communication circuit adapted to be energized by an alternating current source, the combination of a subharmonic generator including transformer means, first winding means on said transformer means for supplying subharmonic output voltage, ringing-current circuit means, talking-current circuit means, means for connecting the ringingcurrent circuit means to said first winding means, first switching means for energizing said subharmonic generator, whereby said first winding means supplies subharmonic current to said ringing-current circuit means, second winding means on said transformer, a rectifier connected to said second winding means, and second switching means for connecting said rectifier to said talking-current circult to supply direct current thereto.

2. In a communication circuit adapted to be energized by an alternating current source, the combination of a subharmonic generator including transformer means, first winding means on said transformer means for supplying subharmonic output voltage, ringing-current circuit means, talking-current circuit means, means for connecting the ringing-current circuit means to said first winding means, first switching means for energizing said subharmonic generator,

whereby said first winding means supplies subharmonic current to said ringing-current circuit means, second winding means on said transformer, a rectifier connected to said second winding means, and second switching means comprising at least first and second contact means, said first contact means connecting said transformer to the alternating current source and said second contact means connecting said rectifier to said talking-current circuit means to supply direct current thereto' 3. In combination, a frequency changer comprising input and output branches, saturable magnetic coupling means coupling said input and output branches in conjugate relationship, a first rectifier, subharmonic load circuit means in said output-branch, a capacitor in a closed circuit in said output branch for exciting subharmonic oscillations therein, means in said input branch for energizing said coupling means through said first rectifier to produce said oscillations and energize said load circuit means, a second rectifier, winding means on said coupling means inductively coupled to said input branch and connected to said second rectifier, direct current circuit means connected to said second rectifier, and means in said input branch for energizing said coupling means independently of said first rectifier to energize said second rectifier and said direct current circuit means.

4. In a telephone circuit the combination of a subharmonic generator comprising input and output branches, saturable magnetic coupling means coupling said input and output branches in conjugate relationship, a capacitor in a closed circuit in said output branch for exciting subharmonic oscillations therein, a rectifier, winding means on said coupling means inductively coupled to said input branch, ringing-current circuit means, talking-current circuit means, first and second switching means, first circuit means controlled by said first switching means for supplying both alternating current and direct current to said input branch to produce said subharmonic oscillations and to energize said ringing-current circuit means therewith, second circuit means controlled by said second switching means for supplying alternating current to said input branch to energize said rectifier from said winding means to supply direct current to said talkingcurrent circuit means.

5. In a telephone circuit, the combination of a ringing-current circuit, a ta1king-current circuit, a subharmonic generator comprising input and output branches, saturable magnetic coupling means coupling said input and output branches 1n conjugate relationship, a capacitor in a closed circuit in said output branch for exciting sub harmonic oscillations therein, a first rectifier serially connected in said input branch, first input circuit means for supplying alternating current through said first rectifier to produce said subharmonic oscillations to energize said ringingcurrent circuit, winding means on said coupling means inductively coupled to said input branch, a second rectifier connected to said winding means, and second input circuit means for supplying alternating current independently of said first rectifier to energize said second rectifier to supply direct current to said talking-current circuit.

6. In a telephone circuit, the combination of a ringing-current circuit, a talking-current circuit, a subharmonic generator, 2. first switch -for connecting said subharmonic generator to a source of alternating current and to said ringing-current circuit, said subharmonic generator including a saturable transformer, winding means on said transformer, a rectifier connected to said winding means, and a second switch for connecting said transformer to said source of alternating 6 current and for connecting said rectifier to said talking-current circuit, said ringing-current circuit being energized with subharmonic current by the operation of said first switch, said talking-current circuit being energized with direct current by the operation of said second switch.

7. In a telephone circuit, the combination of a ringing-current circuit, a talking-current circuit, a subharmonic generator comprising a saturable magnetic coupling uni-t having input and output branches in conjugate relationship, a capacitor connected to said output branch for exciting subharmonic oscillations therein, a half-Wave rectifier connected to said input branch, a first switch having normally open contacts for connecting said input branch to a source of alternating current through said half-wave rectifier and having normally open contacts for connecting said output branch to said ringing-current circuit, winding means on said coupling unit inductively related to said input branch, a fullwave rectifier connected to said winding means, and a second switch having normally open con tacts for connecting said input branch to said source of alternating current independently of said half-wave rectifier and having normally open contacts for connecting said full-Wave rectifier to said talking-current circuit.

8. In a telephone circuit, the combination of a ringing-current circuit, a talking-current circuit, a subharmonic generator comprising a saturable magnetic coupling unit having input and output branches in conjugate relationship, a capacitor connected to said output branch for exciting subharmonic oscillations therein, a half-wave rectifier connected to said input branch, a first switch having normally closed contacts shunting said half-wave rectifier for connecting said input branch to a source of alternating current and having normally open contacts for connecting said output branch to said ringing-current circuit, winding means on said coupling unit inductively related to said input branch, a full-wave rectifier connected to said winding means, and a second switch having normally open contacts for connecting said full-wave rectifier to said talkingcurrent circuit.

9. In combination, a three-legged saturable magnetic core, an input winding on the central member of said core, two output windings one on each outer member of said core, said output windings being connected in series, polarized to substantially cancel voltage induced from said input winding, a half-wave rectifier, means for energizing said input winding from an alternating-current source through said half-wave rectifier, a capacitor connected to said output Windings for exciting subharmonic oscillations therein when said input winding is energized through said half-wave rectifier, subharmonic load circuit means connected to said output windings, a rectifier winding on the central member of said core, a full-Wave rectifier connected to said winding, direct current load circuit means connected to said full-wave rectifier, and means for energizing said input Winding from said source independently of said half-wave rectifier.

10. In combination, a three-legged saturable magnetic core, an output Winding on the central member of said core, two input windings, one on each outer member of said core, said input windings being connected in series and polarized to produce opposing fluxes in said central member, a half-Wave rectifier, means for energizing said input windings from an alternating-current wave rectifier connected to said windings, direct 10 N b current load circuit means connected to said fullwave rectifier, and means for energizing said input windings from said source independently of said half-wave rectifier.

HENRY MARTIN HUGE,

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date 2,323,307 Campbell July 6, 1943 

